Process for the flotation of fluorite

ABSTRACT

Improvement in flotation of calcium fluoride from claycontaining ores which comprises conditioning the flotation slurry with an alkyl phenol ethoxide and a fatty acid ethoxide prior to adding the usual flotation reactants. Flotation slurry may be prepared from common calcium fluoride crude ore or from clay slime discarded from prior flotation processes.

Unite States Patent [72] lnventors Giovanni Perri;

Glanfranco Aquili, both of Novara, Italy [21] Appl. No. 1,851 [22] Filed Jan. 9, 1970 [45] Patented Nov. 30, 1971 [73] Assignee Montecatini Edison S.p.A.

Milan, Italy [32] Priority Jan. 9. 1969 [33] Italy [31] 1l3l0A/69 [54] PROCESS FOR THE FLOTATION 0F FLUORITE 7 Claims, No Drawings References Cited UNlTED STATES PATENTS 2,300,827 11/1942 Christmann 209/166 2,757,797 8/1956 Eckert 209/166 X 2,803,345 8/1957 Jacobs.. 209/166 3,179,250 4/1965 Bunge 1. 209/166 3.430.765 3/1969 Allen 1 209/166 X FOREIGN PATENTS 142,232 3/1961 U.S.S.R......,. 252/6l 782.107 9/1957 Great Britain 252/61 OTHER REFERENCES A P C Application of Goette Ser. No. 274.858. Published .luly13. 1943.

Primary Examiner- Frank W. Lutter Assixlanl Examiner-Robert Halper Anorney- H ubbell, Cohen & Stiefel ABSTRACT: Improvement in flotation of calcium fluoride from clay-containing ores which comprises conditioning the flotation slurry with an alkyl phenol ethoxide and a fatty acid ethoxide prior to adding the usual flotation reactants. Flotation slurry may be prepared from common calcium fluoride crude ore or from clay slime discarded from prior flotation processes.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for the flotation of CaF more particularly, to an improved process for separating, by flotation, the calcium fluoride from the crude ore, wherein it is in admixture with gangues and clays.

2. Description of the Prior Art It is known that the beneficiation of the ores by flotation is often influenced by the clay-containing substances present in the crude ore. Especially in the flotation of nonmetallic minerals, the sludges of the flotation slurry, that is, the clays contained in such sludges, adversely affect the recovery efficiency and amount of the reactants consumed.

In order to overcome this drawback, in general, resort has been had to the preliminary desliming of the slurry, or, when possible, to the neutralization of the effects of the clays by means of suitable reactants.

The desliming operation, however accurately conducted, involves losses in the useful component that one wishes to beneficiate. These losses increase with intensified grinding and with decreased hardness of the valuable component.

The neutralization of the sludges by means of specific reactants, while having found widespread application in recent years, does not provide an entirely satisfactory solution to the problem since the reactants used not only depress the flotability of the sludge but also of the other, desirable components of the flotation slurry, thereby increasing the loss of the mineral sought to be recovered.

In the particular case of the fluorite minerals, i.e., CaF the sludge presented a particularly difficult problem because no specific reactant was known that would neutralize the sludges without appreciably reducing the flotability of the CaF The lack of specific reactants compelled one to resort to physical desliming of the slurry, also with considerable losses of fluorite. In fact, since the fluorite is a rather soft mineral and since it is necessary to employ rather intensive grinding in order to free the granules, there occurs an accumulation of CaF in the finest fractions which are removed with the sludges. The losses of CaF due to the desliming sometimes amount to percent by weight of the CaF contained in the raw material.

The mining industry over the years has accumulated this muddy material or slime in suitable basins, generally located near the processing installations, in the hope of eventually being able to recover the Cal contained in the slime. In these basins the fine fractions ofthe flotation wastes that contain appreciable quantities ofCaF are also collected.

SUMMARY OF THE INVENTION This invention provides means for recovering the fluorite contained in the muddy material or slime in the collection basins as well as for obtaining from such slime or from normal crude ore a CaF- product of an acid degree (that is, with a CaF titre higher than 95 percent and with a useful Cal titre higher than 91 percent; the useful CaF being defined as the total CaF less 4 times the weight percent of SiO More particularly, we have found new reactants which, used together with those previously employed for the flotation of fluorite, provide a simple and inexpensive solution to the problem.

In accordance with the present invention, an ethoxylated alkyl phenol and an ethoxylated fatty acid are employed to condition the ore prior to flotation. Thus, we have surprisingly found that the ethoxylated alkyl phenols depress the sludges without interfering with the flotability of the fluorite whereas, on the contrary, the previously known common depressors of the sludges also decrease the flotability of the fluorite. Moreover, we have surprisingly found that the ethoxylated fatty acids act as strong activators of the fluorite flotability, particularly the fine fluorite which is accompanied by very fine gangue.

LII

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ethoxylated alkyl phenols, also called alkyl phenylpolyethylene glycols, are generally obtained by reaction of an alkyl phenol with ethylene oxide. They have, as a substituent on the phenyl radical, an alkyl having from nine to l5 carbon atoms, and contain from l0 to 16 glycolic groups, CH CH O.

These compounds are described as surfactants, for example, in J. P. SISLEY-Index des detergents-Editions Teintex, Paris (wherein they are classified in class III/C and are called polyethoxy ethers of alkyl phenols); A. M. SCHWARTZ, J. W. PERRY-Surface Active Agents and Detergents-Interscience Publishers, New York l966)Vol. II, page I25; Mc- CUTCHEONs-Detergents and Emulsifiers-DAE I966 Annual-Morristown, NJ.

These nonionic surfactants are produced industrially in great quantities and are easily found on the market. These commercially available products include, for instance the Tergitols of Union Carbide Corp., such as: Tergitol l2-P-9, Tergitol l2-P-l0, Tergitol l2-P-l2 dodecylphenyl-polyethylene glycol ethers); the Igepal CA and Igepal C0 of General Aniline & Film Corp; the Sapogens A of Anorgana Gendorf; the Hostapals C of Farbwerke Hoechst; the Carboxanes of Testilana Corp.; and the Tritons X of Rohm & Haas.

The ethoxylated fatty acids, also called polyoxyethylated fatty acids or, better still, polyethyleneoxy esters of the fatty acids, are obtained by reacting the fatty acid with ethylene oxide or with a polyethylene glycol. The polyethyleneoxy esters used in the process of the present invention are formed from a fatty acid having from 12 to 20 carbon atoms and from l0 to 20 -CH CH O(oxy ethylene) groups, They are, for instance, described in Sisley (loc. cit.) wherein they are classified in class III/B and are called polyethoxy esters of fatty acids; in Schwartz (loc. cit. on page I30); and in Mc- Cutcheons (loc. cit.).

These anionic surfactants are also produced on an industrial scale in large quantities and are easily found on the market.

Commercial products of this kind include, for instance. the Emulphors of Sinnova Sadic Company, of BASF and of General Aniline & Film Corp. (obtained from oleic acid, castor oil, talloil and ethylene oxide; the Emulsenes of Sapchim-Fournier-Cimig; the Ethofats of the Armour lndustrial Chem. Co.; and the Lipals E and S of Drew Chemical Corp.

The preparation or conditioning of the mineral may be carried out in accordance with the present invention in the following way:

The muddy material is pulped in water to form a slurry having a solids content of IS to 30 percent by weight. The slurry thus obtained is conditioned for l-l0 minutes, preferably from 2 to 4 minutes, with polyethyleneoxy alkyl phenol (I00 -200 g./t. [grams per metric ton] of dry solid) and then for an additional 1 to 10 minutes, preferably from 3 to 5 minutes, with the polyethyleneoxy ester (200-300 g./t. of dry solid). The slurry thus prepared is ready for being conveyed to flotation, which latter operation is carried out with the known reactants and with the usual technique.

Thus, for the flotation, the following reactants are then added to the already conditioned slurry. (The quantities depend on the composition of the mineral treated.) An unsaturated fatty acid, such as oleic acid, as collector for the CaF (it forms a water-repellent coating on the fluorite granules); from 250 to 500 g./t, of solids are used, according to the fluorite contents of the slurry.

A starch (e.g. corn starch), as depressor of the silica, in quantities offrom 500 to I500 g./t. of solids,

Sodium fluoride as activator of the fluorite, in quantities of from 300 to 800 g./t. of solids (the sodium fluorite may be totally or partially replaced by the polyethyleneoxy ester).

A tannin, such as quebrache, for depressing the calcite in the successive flotation runs of the concentrate, in quantities offrom to 200 g./t. of solids.

The reactants are added under stirring, in short time intervals from each other in accordance with common prior art flotation procedures. The polyethyleneoxy ester, an activator for the fluorite, may be added together with the flotation reachad a mineral/water weight ratio of l:2.5. The consumption of reactants is expressed in grams/ton (metric) of dry solid.

The results of the test are recorded in table lA. As can be seen from this table, the concentrate thus obtained displayed a tants. Once the addition of the reactants has been completed, 5 fair CaF titre, but was not of acid degree." Moreover, the the slurry is conditioned for some minutes (usually 2-20 recovery is quite low (6l.25 percent). minutes), then air is blown into the slurry and the mass is Another test was carried out on the same slimy material emfloated up to exhaustion of the mineralization of the foam (5 ployed in the preceding test, using, however, the to 10 minutes). The concentrate of the first flotation (rough or polyethyleneoxy reactants in accordance with this invention. primary concentrate) is floated again (reflotation or rerun) 10 The operational procedures have been indicated in table 2. for three or four times until obtaining an definitive concen- The slurry had a solid/water weight ratio of l:2.5 The contrate of an acid degreeashereinabove defined. sumption of reactants is expressed in grams per ton of dry The conditioning of the slime, carried out with the foregosolid. The results obtained are recorded in table 2A. The final ing polyethyleneoxy reactants in accordance with the process concentrate showed a titre in carbonates of l.l0 percent and of the present invention, provides for the first time a method in silica of 0.9 percent; thus, it is of an acid degree. The for obtaining by known flotation methods a concentrate of recovery was good,about 85 percent. fluorite of an acid degree" and with high yields (greater than 80 percent). EXAMPLE 2 AS Previously mentioned conitioning W P A test was carried out on a tout-venant mineral, without lar reactants in accordance with this invention may also be physical deSHmI-ng' according to the known technique carried out on the raw mineral (tout-venant), in particular on The raw Substance was ground to below 55 mesh Tyler the clay-containing raw materials; in the case of tout-venant The granulometric analysis was the f ll i ore, the pulp can contain up to 50 percent solids. With this treatment the need for any desliming operation is eliminated Mesh By wish with the advantage of the thereby eliminating a processing phase and. moreover, of obtaining a greater yield of fluorite. 65 +10, (The conditioning is, naturally, followed by flotation by loo-+150 22.0% known methods.) 151F400 The following examples are given to further illustrate th 2x1 5:23: present invention and are not intended to limit the scope 3O 4 thereof. The conditions of the test are indicated in table 3. while the results are recorded in table 3A.

Another test was carried out on the same mineral of the EXAMPLE 35 (preceding test, using the known technique, but effecting a esliming of the slurry before the flotation. The operational A test was carried out on a slime, containing, on a dry basis, conditions are indicated in table 4, while the results are 37.50 percent by weight of CaF 39.83 percent by weight of recorded in table 4A. SiO,, 8.55 percent by weight of carbonates, with the A third test was carried out on the same mineral as used for remainder l4.l2 percent) being made up of clay and various the two preceding tests, without desliming the slurry, using, oxides. The granulometric analysis indicated that 87 percent however, the particular surfactant agents in accordance with by weight of the sample had a particle size below 400 mesh this invention. U.S. Tyler (0.034 mm.), and that 70 percent by weight of the The operational conditions are indicated in table 5, while sample comprised very fine substances, below 20 microns in the results are recorded in table 5A. diameter. The test was carried out by the known technique From the titre in the final concentrate and from the yield, (described in Revue de llndustrie Minrale" [i967], l-9) the advantage of the process of the present invention is according to the procedures summarized in table 1. The slurry evident.

TABLE 1 Consumption of reactants in gJt. (mixture) Chromium Time Sodium I I Sodium Acintoi in Operations silicate sulphate Starch fluoride FAl min.

Conditioning 350 140 2,000 800 5 Conditioning 400 6 Roughing flotation... 100 10 1st re-run 28 170 7 28 200 170 5 28 200 170 100 5 28 200 170 5 No'rE,-The Aclntoi FAl of Arizona Chemical Co, is an emulsified mixture of unsaturated fatty acids obtained from talloil,

TABLE 1A Composition, percent Distribution, percent Weight Products percent CaFz MCOH SlO: CaFz MOO; SiOi Feeding 100.00 37. 8. 39. 83 100. 00 100. 00 100. 00 Roughing flotation:

'lIaiiing 54. 50 8. 98 7. 42 63. 25 13. 07 47. 40 86. 69

Concentrate 21.... 45. 50 68. 56 8. 87 14. 61 86. 93 52. 13. 41 1st run of concentrate a:

Tails 8. 00 28. 30 14. 50 37. 90 6. 03 13. 56 7. 60

Concentrate b 37. 50 80. 88 8. 90 6. 16 80. 90 39. 04 5. 87 2nd rim of concentrate b:

Tails 6. 50 43. 25. 40 20. 7. 57 19. 29 3. 39

Concentrate c 31. 00 88. 70 5. 45 3. 09 73. 33 19. 75 2. 42 3rd run of concentrate c:

Concentrate d 26. 50 94. 21 2. 2. 18 66. 58 9. 00 1. 45 4th run of concentrate d: Tails. 2. 50 80. 2 10. 70 4. 35 5. 33 3. 16 0. 27 Final concentrate 24. 0G 95. 7 2. 10 i. 61. 25 5. 84 1. 18

N ore-M003 denotes carbonates and hydroxides,

acetic acid.

usually of Ca and Mg, soluble in TABLE 2 Consumption of reactants in g./t.

Aionico Aionico Emulsified Time in Operation F. 560 T. 510 Dextrine olein Quebrache min.

Conditioning 300 2 Do 400 2 Do.. 1,000 3 Roughing flotation. 1st re-run.. 4 2nd re-run... 4 3rd re-run 4 4thre-run... 4

NorE.The surfactant Aionico D, 560" is a Montecatini Edison S.p.A. product; it is a dodecylphenol having 12 groups of ethylene oxide. The surfactant Aionico T. 510 is a Montecatini Edison S.p.A. product; it is a condensation product of Tall oil with 17 molecules of ethylene oxide.

TABLE 2A Composition, percent Distribution, percent Weight Products percent CaFz M001 S102 CaFz MCOa S102 Feeding 100.00 37.60 8.66 39.83 100.00 100.00 100.00 Roughing flotation:

Tailin 63.00 2.66 8.41 64.64 3.63 62.13 86.89 Concentrate a 47.00 76.89 8.70 11.96 96. 37 47. 87 14.11 1st re-run of concentrate a:

ails 6. 00 8. 50 30. 20 50. 1 36 21. 22 7. Concentrate b 41.00 86. 90 6. 56 6. 36 96.01 26. 66 6. 66 2nd rerun of concentrate b:

Tails 4. 60 28. 60 28. 40 36. 60 3. 41 14. 97 3. 99 Concentrate c 36. 60 94. 10 2. 73 2. 79 91. 60 11. 68 2. 67 3rd re-run of concentrate c:

Tails 2. 60 50. 00 22. 6 26. 30 3. 34 6. 64 1. 65 Concentrate d 34. 00 97. 34 1. 26 1. 06 88. 26 6. 14 0. 92 4th re-run of concentrate d:

'1 1.40 89. 00 5. 4. 3. 33 1.04 0. 19 Final concentrate 32. 60 97. 70 1.10 0.90 84. 93 4. 10 0. 73

TABLE 3 Consumption of reactants in g./t. (mixtures) Chromium Emul- Time Sodium III Diapon Dex- Sodium sified Quebrain Operations silicate sulphate T trine fluoride olein cho mins.

Conditiomn' g 350 3 Do 800 200 15 Roughing flotation 7 1st re-run 70 5 70 4 3rd re-run 70 4 Nora-The sm-iactant Diapon T" is produced by Montecatini Edison S.p.A.; it is the sodium salt of N- methyl-N-oleyl-taurine.

TABLE 3A Composition, percent Distribution, percent Weight Products percent CaFz MCOa SiOz CaFz M00: SiOz Feeding 100 65. 00 6. 80 31. 20 100 100 100 Roughing flotation:

Tai1ing 60.20 25.83 8.69 63.00 23.69 64.20 86.29 Concentrate a-.. 49. 80 84. 39 4. 88 3. 21 76. 41 36. 80 14. 71 1st re-run of concentrate a:

Tails.-. 8. 70 42. 30 16. 50 36.10 6. 69 21. 10 10. 06 Concentrate b 41.10 93. 30 2. 43 3. 62 69. 72 14. 70 4. 66 2nd re-run of concentrate b:

ails 4. 60 65. 30 12. 50 19. 50 5. 35 3. 27 2. 81 Concentrate c-.. 36. 60 96. 73 1.19 1. 66 64. 37 6. 43 1. 84 3rd re-run of concentrate c:

T 1.80 84.10 6.80 8.50 2.67 1.83 0.51 Final concentrate 34. 80 97. 70 0. 90 1. 20 61. 80 4. 60 1. 33

TABLE 4 [The slurry shows a solid/liquid ratio equal to 1:16]

Consumption of reactants in g./t. (mixture) Time Sodium Chromium Diapon Emulsified i Operations sllicate III sulphate T Dextrine olein Quebrache mins.

Conditioning 3 D0 n. 5 Roughing flotation 7 1st re-run 5 2nd re- 4 3rd 1'6- 4 TABLE 4A Composition, percent Distribution, percent Weight Products percent OaFz M003 SiOz CaFz MCOa S102 Feeding 100 55.90 6.80 31.20 100 100 100 De-slimingsludge-.. 9.70 68.20 7. 30 18. 60 12.04 10.42 5. 76 DeSlimed toutvenant 90.30 53.56 6.74 32.55 87.96 89.58 94. 24 Roughing flotation:

Taiiing 39.10 10.43 8.95 65.35 1.42 51.47 81.91 Concentrate a.-. 51.20 86.52 5.06 7.51 80.64 38.11 12.33 151; re-run of concentrate a:

Tails-. 6.70 28.48 26.35 40.35 3.47 25.96 8.66 Concentrateb 44.50 95.25 1.85 2.57 77.07 12.15 367 2nd rerun of concentrate b:

Tails 2.80 62.53 13.64 21.75 3.18 5.61 1.95 Concentratec.. 41.70 97.46 1.06 1.28 73.89 6.54 1.72 3rd re-I'un of concentrate or Tails 1.20 83.80 8.30 7.40 1.83 1.48 0.30 Final concentrate 40.50 97.85 0.86 1.10 72.06 6.06 1.42

TABLE [The slurry shows a solid/liquid ratio equal to l :1.5]

Consumption of reactants in g./t.

Time Aicnico Aionico Diapon Emulsified in Operations D. 560 'I. 510 T Dextrine olein Quebrachc mins.

7 5 4 3rd re-run 4 TABLE 5A w h Composition, percent Distribution, percent cig t Products percent CBF: M00 SiO; Cal MO 0; S10

Feeding. 100 55. 00 6. 80 31. 100 100 190 Tailing 40. 40 8. 9. 03 60. 38 6. 06 53. 63 85.96 59. 60 86. 69 5. 29 7. 93. 94 46. 37 14. 04

7. 29. 42 27. 44 39. 26 4. 01 30. 26 9. 44 Concentrate b- 52.10 94. 93 2.10 2. 89. 93 16. 11 4. 60 2nd re-run of concentrate b:

Tails 2. 60 61. 48 13. 22. 76 2. 91 5. 29 1.89 Concentrate c. 49. 50 96. 69 I. 48 1. 71 87. 02 10. 82 2. 71 3rd re-nm of concentrate at 1. 8O 63. 07 16. 70 18. 35 2. 07 4. 42 1.06 Final concentrate 47. 70 97. 96 0.91 1. 08 84. 6. 40 1. 65

Variations can, of course, be made without departing from P of high acid g the spirit and scope of the invention.

Having thus described our invention. what we desire to secure by Letters patent and hereby claim is:

1. in a flotation process for the recovery of fluorite from clay-containing ores. the improvement which comprises, prior to carrying out conventional flotation. conditioning a flotation slurry by treating said slurry for a period of from about i to 10 minutes with from about 100 to 200 grams per metric ton of slurry solids of a polyethyleneoxy alkylphenol, and thereafter treating said slurry for a period of from about 1 to 10 minutes with from about 200 to 300 grams per metric ton of slurry solids of a polyethyleneoxy ester of a fatty acid. said polyethyleneoxy alkylphenol being made up of (I) an a] kylphenol radical in which the alkyl has from about 9 to [5 carbon atoms and (2) from about 10 to 16 ethyleneoxy units, and said polyethyieneoxy ester being made up of l) a fatty acid having from about 12 to 20 carbon atoms. and (21 from about 10 to 20 ethyleneoxy units and floating a fluorite 2. The process of claim 1 wherein said treatment with said polyethyleneoxy alkylphenol is carried out for from about 2 to 4 minutes.

3. The process of claim 1 wherein said treatment with said polyethyleneoxy ester of a fatty acid is carried out for from about 3 to 5 minutes.

4. The process of claim 1 wherein said polyethyleneoxy alkylphenol is made up of a dodecylphenol and 12 ethyleneoxy units.

5. The process of claim 1 wherein the fatty acid for said polyethyleneoxy ester is tall oil. and said ester contains 17 ethyleneoxy units.

6. The process of claim 1 wherein said flotation slurry comprises an aqueous suspension of a raw material ore.

7. The process of claim 1 wherein said flotation slurry comprises fluorite-containing slime and flotation wastes discarded from prior flotation processes.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 623 605 Dated November 30, 1971 Inventor) Giovanni Perri, Gianfranco Aquili It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 19 "for instance" should read for instance, line 44 "Cimigg" should read Cimag;

Column 4, Table 1A, under the heading "Distribution, percent" third column headed "SiO line 5, "5.87" should read 5. 81

Column 5 and 6, Table 3 the heading of the eighth column, "Quebracho" should read Quebrache Table 3A, under the heading "Composition, percent" third column headed "S110 line 3 "3 21" should read 9 21 Column 7, line 49, "Leters patent" should read Letters Patent Column 8, line 60 (claim 6, line 2) "raw material ore." should read raw mineral ore.

Signed and sealed this 10th day of October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. The process of claim 1 wherein said treatment with said polyethyleneoxy alkylphenol is carried out for from about 2 to 4 minutes.
 3. The process of claim 1 wherein said treatment with said polyethyleneoxy ester of a fatty acid is carried out for from about 3 to 5 minutes.
 4. The process of claim 1 wherein said polyethyleneoxy alkylphenol is made up of a dodecylphenol and 12 ethyleneoxy units.
 5. The process of claim 1 wherein the fatty acid for said polyethyleneoxy ester is tall oil, and said ester contains 17 ethyleneoxy units.
 6. The process of claim 1 wherein said flotation slurry comprises an aqueous suspension of a raw material ore.
 7. The process of claim 1 wherein said flotation slurry comprises fluorite-containing slime and flotation wastes discarded from prior flotation processes. 